Thermostatic switch



Jan. 19 1926.

R. H. HOUK 'rmmmosgmuc SWITCH Filed July 20, 1922 ww wvw w NKWQWN attozucqs till Patented Jan- 19, 1926.

UNITED STATES sonar 1:. noux,- or :ronnrr, tumors.

THERMOSTATIC SWITCH.

Application filed July 20, 1922. Serial No. 576,387.

To all whom it may concern:

Be it known that I, Ronnu'r H. HOUK, a citizen of the United States, residing at Joliet, in the county of Will and State of Illinois, have invented new and useful Improvements .in Thermostatic Switches, of which the following is a specification.

This invention relates to electric switches which are controlled b a thermostat, and its object is to provi e a switch of this kind embodying certain novel andim roved features of construction and modes 0 er ation as will be pointed out in the detailed description appearing hereinafter.

In order that the invention may be better understood, reference is had to the accompanying drawings, wherein:

Figure'l is an elevation of the complete apparatus,

Fig. 2 is a vertical section on the line 2-2' of Fig. 1, and

Fig. 3 is a detail'view of a modification.

Referring specifically to the drawings, denotes a suitable base which supportsthe apparatus. The thermostatic element is a bent tube 11 having one of its ends rigidly fastened to the base, its other end being left free so that it may move in a direction outwardly of the first-mentioned end in response to a temperature increase, and toward the latter in response to a drop in. tem erature.

T is base 10 also supports a dial plate 12 across which is movable a pointer 13 carried by an arm 14 of insulating material. The arm '14: is pivoted at one end, and its other end carries the pointer 13, said lastmentioned end being slitted, as shown 15, to straddle the plate 12.

Into the base plate 10 and through a metal plate 16 secured to the face ot the till base plate 10 is passed a screw 16" which passes loosely through a small cylindrical block 17 having a reduced bottom portion 17" which seats in an aperture 14 in the rear or inner end 01 the arm 14, whereby the pivotal mounting of said arm is obtained. The forward end-cf the arm 1 1 carrying the pointer 13 also carries a pair oi spring fingers 18 which bear against the under side of the plate 12 with suilicient pressure so that the arm 14.- works tight and remains in the position it may be placed.

The screw 16" ivotally supports a switch arm 19 ct insu ating material extending parallel to thearm 1t and adapted to swing .of the latter to a limited de the screws 21.

One side of theelectrie circuit to be controlled is connected to the bracket 20, and the other side is connected to the finger 22. The bracket 20 and the finger 22 are made of brass or other electro-conductive material. On the base lOare mounted bind ing posts 23 to which the main circuit wires 2 1 are connected, and from these binding posts, conductors 25 are carried to the bracket 20 and the finger 22, the connections being made by suitable clips 26. The base 10 also carries a guide and clamping member 27 for the conductors 25.

The movement of the thermostatic element 11 is adapted to be transmitted to the switch arm 19 by means of a bar 28. One end of this bar is threaded, as shown at 28, and passes loosely through an car 11 on the free end of the element 11. Lock nuts 29 carried by the threaded end 28 of the bar 28 rigidly couple the same to the free end of the element 11 upon running said nuts on the threaded end in a direction to tightly engage opposite sides of the ears 11. lantermediate its ends, the bar 28 has a recess 28" into which extends a pin 30 extending downwardly from a plate 3O secured to the bottom of the arm 19. The plate 18 carries a guide 31 for the bar 28.

The ap aratus is designed to be adjusted to respon to a variation in any desired degree or": temperature. This is done by swinging the arm'lt to bring the pointer 18 to the graduation on the'dial 12 denoting the degree of temperature which is to be maintained. Before this can be done, the lock nuts 29 must be hacked to uncouple the bar 28 from the free end of the thermostatic element 11, and after the arm has been swung to set the pointer as described, the loch nuts must be operated to again couple the bar to the thermostatic element. To facilitate the setting oi the pointer 13, the

arm 14 has a knob 32 back of the former. The switch arm 19 carrying the contact finger 22 swings with the arm 14 and hence said finger follows the switch contact points formed by the screws 21. If now there is a rise in temperature, the free end of the thermostatic element moves outwardly, andv through the bar28 and its connection with the switch arm 19 through the pin 30, said arm is made to swing to bring one of the branches 22 of the contact finger 22 into contact with the opposite screw 21, thereby closing the electric circuit. When a drop in I temperature occurs, the parts move in the opposite direction to that just described, and the other branch of the contact finger swings over to engage the opposite contact .screw, so that the circuit is again clbsed.

The switch can be used in connection with any electro-responsive apparatus, such as a magnet for sounding an alarm, or a motor for operating a valve or any other mechanism. The preferred embodiment of the invention has been disclosed but it will be understood that various changes and modifications may be made without a departure from the spirit and scope of the invention as claimed hereinafter. Fig. 3 shows 'one of these modifications. Here, the bar which provides the operative connection between the thermostatic element and the movable switch arm 19, is a rack bar 32 which is in meshes mesh with .a pinion 33 carrying the switch arm. Various other modifications will readily suggest themselves to those skilled in the art to which the invention pertains.

I claim;

A thermostatic switch comprising a base, a dial secured to the base, a main pointer arm of insulating material having its upper portion formed with a slot receiving the lower edge portion of said dial, a spring carswitch arm, said slot ing extended at right angles to the axis ofthe bar and having side we ls in-engagement with said pin whereby the longitudinal'movenient of the bar will operate said .pinand the switch arm carryin' the pin, and a thermostat connected to said ar. i

In testimony whereof I afiix my signature.

ROBERT H. HOUK. 

